I don’t think you quite understand how the uncanny valley works. Those imperfections you don’t want to add are a part of real people’s faces. The sort of perfection you see in glossy magazines is created by a combination of heavy makeup, clever lighting, and photoshopping of the image, all of which has the ultimate effect of forcing real people back into the uncanny valley you claim to want to avoid. If you want to avoid the uncanny valley, you need those small imperfections and asymmetries. The lack of these is the human brain’s easiest clue that the image is not real. If you’re bound and determined to make a model with no wrinkles, imperfections or asymmetries, not even subtle ones, your quest is doomed already.
As for your model specifically, it looks like you have a good mesh and reasonably good materials. Though I’m not sure about the skin shader. It’s hard to tell if it’s the shader, the lighting, or the low sampling you’ve used, but the skin looks off, a bit plastic. The color is good but perhaps the gloss is too uniform across the surface. Again, it’s hard to tell where the problem is coming from, but I suspect it’s all of the above. It doesn’t look like you’re using any environment here, so already you’re losing some of what makes an image look real. Even in a clean studio a person is not just lit by invisible lamp objects hovering in mathematical space. Real lamps have shape and imperfections of their own, and light is bouncing off of other surfaces in the room. I’d recommend getting a good HDRI for your scene before proceeding any further, and use this low sample setting only for checking progress along the way, not for critique renders.
It also looks like you’re only using one hair system. It’s nearly impossible to replicate the look of real hair that way, because there are always misbehaving hairs. You have hairs of differing thicknesses, curliness and age, so even a well-groomed model will have some flyaway hairs and such. A second and possibly even third layer of hair particle systems can help accomplish this. The hair shader itself looks pretty good, but could use a bit more variation. Are you using a texture to vary the hair color somewhat across the head, or have you just set some basic colors?
The lips look pretty good, nicely textured, though even a young woman should have some smile lines. Again, real people have wrinkles, even the pretty and innocent ones. The corners of her eyes should have some subtle wrinkles as well. That level of smoothness just looks painted on.
As for the “feeling” this image has none at all currently, because it appears to just be a test render of an un-posed model. She has no expression on her face at all. She isn’t doing anything and the background is black. There is no environment or setting to give context, and with generic colorless studio lighting there isn’t anything to give the image itself a mood. It’s an emotionless model on an emotionless background with emotionless lighting with the camera placed at an emotionless angle. It isn’t enough to just have a model that looks quite a bit like a young girl. That is not enough to convey the feelings you’ve listed. Image composition, lighting and setting, and the model’s pose and facial expression all need to contribute to that.
